PowerPoint Learning Quest Biology 9 Unit 2: Basic Matter of Biology Created by Jeff Wolf and Mike Graff

PowerPoint Learning Quest

Biology 9

Unit 2: Basic Matter of Biology

Created by Jeff Wolf and Mike Graff

Objectives: After completing this Learning Quest the student will…

Review and describe the structure of an atom including defining what protons, neutrons, and electrons are.Describe the key elements needed for a human body.Indicate the human disorder or deficiency due to the lack of a certain element.Describe four life supporting properties of water.Explain the differences between a Basic Solution, a Neutral Solution, and a Acidic Solution using the pH scale. What is the significance of the pH to enzyme function.

Directions

1. Follow the instructions in the Anticipation Guide found in this PowerPoint Presentation.

2. Follow the instructions and answer all questions found in the Learning Guide.

3. Follow the instructions in the Conclusion Guide.

4. ALL THREE GUIDES CAN BE FOUND IN THIS LEARNING POWERPOINT QUEST.

Anticipation Guide (Page1)

Atoms are the smallest unit of matter that still retains the properties of an element.Atoms consist of protons, neutrons and electrons, the important particles of an atom. One or more atoms that cannot be broken down to other substances are called elements.SEE YOUR TEACHER TO DICUSS THE COMPREHENSION OF THESE KEY CONCEPTS.

Nucleus

Cloud of negativecharge (2 electrons)

(a)

(b)

2 Protons

2 Neutrons

2 Electrons

Learning Guide (Page 1)

Elements are a essential part of the human body. Without certain chemical elements the human body could not survive. Four key elements: Oxygen, Carbon , Hydrogen, and Nitrogen are very significant in the development and growth of all human beings. Approximately 96% of these four elements make up the weight of the entire human body.Overall (as the diagram to the left demonstrates) there are at least 25 different chemical elements needed for the human body to survive.


Although many of the 25 elements found in the body make up 0.01% of the human body they are all important in sustaining life. For example, a Goiter, which is caused by an enlargement of the thyroid gland (see the picture to the right) occurs when a person’s diet does not include a sufficient amount of iodine, a trace element. Goiters have been reduced in many nations by adding iodine to table salt.


When two or more element molecules come together a chemical bond is formed. Three common bonds that can be created include: Ionic bonds, Covalent bonds, and Hydrogen bonds.An Ionic bond is formed when an attraction between oppositely charged ions occur. A good example of an ionic bonded substance is Sodium Chloride (Table Salt). When a positive sodium ion (Na+) comes into contact with a negative bonded chloride ion (Cl-) the two elements are held together by an ionic bond.

Figure 2.8

Chlorine atom (Cl)

Complete outer shells

Sodium ion (Na) Chloride ion (Cl)

Sodium chloride (NaCl)

Sodium atom (Na)


The second bond most often seen in biology is the Covalent bond. Covalent bonds form when two atoms share one or more pairs of outer-shell electrons. Hydrogen gas, Oxygen gas, Methane, and Water are all covalent bonded substances.


The third most common bond seen in biology is a hydrogen bond. Hydrogen bonds occur when polar molecules (opposite charged molecules on opposite ends) such a hydrogen (H+) attracts to an oxygen molecule (O-). The polarity of water results in weak electrical attractions between neighboring water molecules

()

Hydrogen bond()

()()

()

()

()()

H20

H20

H20

H20

H20

Learning Guide (Page 6 )

Organic Compounds vs. In organic Compounds.– “It is as difficult to imagine life without carbon as

it is life without water. Although a cell is mostly water, most of the rest of it consists of carbon-based molecules. Proteins, DNA, fats, carbohydrates, and other molecules that distinguish living matter/organic from inanimate/inorganic material are all composed of carbon atoms bonded to one another and to atoms of other elements. Carbon is unparallel in its ability to form the large complex diverse molecules that characterize life on Earth. The study of carbon compounds is called organic chemistry. Carbon has the capability to form 4 covalent bonds.

Carbon skeletons vary in length

Carbon skeletons may be unbranched or branched

Carbon skeletons may have double bonds,which can vary in location

Carbon skeletons may be arranged in rings


Two of these key elements, hydrogen and oxygen create an important compound that is essential not only to human life but to life in general. That compound is water.Water’s ability to support life is or next topic of discussion.Text pages – 32 through 34.


To understand water’s life supporting properties it is important to know the structure of water. Water or H20 is made out of two hydrogen atoms and one oxygen atom. This combination creates a polar molecule. A polar molecule attracts towards other molecules. Therefore water molecules have a particular tendency to “stick” together. This is called cohesion.

Microscopic tubes


Cohesion is important to the living world and especially important to tall trees. Tall trees rely on cohesion to help transport water from their roots to their leaves. Water not only supplies cohesion for all life forms but also provides a form of surface tension by coating many life forms with an invisible protective film. As seen in the picture to the left, the tiny water strider is able to walk across water because of the surface tension the hydrogen bonds have created between water molecules. The hydrogen bonded water molecules creates a surface in which the insect will not break.


The second life supporting property of water we will discuss in this lesson is water’s ability to moderate temperature.If a scientist were to measure the temperature of a metal pot filled with water the scientist would discover that the metal pot heats much faster than a the water within the pot. The reason for this difference in temperature is that the water’s hydrogen bonds resist temperature change compared to most other surfaces.


The third life supporting property of water is water’s ability to create ice.When most liquids are cooled their molecules move closer together in order to form a solid.Water, on the other hand reacts differently than other liquids placed under extreme coldness. Water (H20) molecules will move apart forming a solid we know as ice.


When water molecules expand to form ice, less molecules are needed to produce a state of solid matter. Therefore, with fewer molecules than any other liquid, ice floats because it is less dense than liquid water.

Hydrogen bond

Liquid waterHydrogen bonds

constantly break and re-form

IceStable hydrogen bonds


The fourth life supporting property of water is water’s ability to be a solvent for life forms. When salt is place into a glass of water the result is a solution. A solution is a liquid consisting of a homogeneous (similar) mixture of two or more substances. When the concoction is mixed you have two substances, the dissolving agent is called the solvent and the substance that is dissolved is a solute.

Ion in solutionSalt crystal


When water is the solvent, the result is called an aqueous solution. Water is the solvent inside all cells, in blood, and also in plant sap. Thus water assists cells, blood and plant sap to dissolve food particles for important nutrients.


In the aqueous solutions within an organism, most of the water molecules are intact. However, some of the water molecules actually break apart into either hydrogen (H+) ions or hydroxide (OH-) ions. The chemical compound that donates H + ions is called an acid.The chemical compound that removes H+ ions from a solution by adding OH – ions is called a base.Refer to textbook pages 34- 36.


The diagram to the left is a pH scale. The pH scale is used to describe the acidity of a solution. The scale ranges from zero (most acidic ) to 14 (most basic). The scale to the left shows various solutions and their equivalent pH.

Basicsolution

Neutralsolution

Acidicsolution

Oven cleaner

Household bleach

Milk of magnesia

Seawater

Human bloodPure water

Urine

Tomato juice

Grapefruit juice

Lemon juice;gastric juice

pH scale

Conclusion Guide (Page 1)

1) The Nucleus of the atom is made up of…

A. Protons and neutrons.B. Protons and electrons C. Elements and Compounds.D. Sols and Gels.

2) Define the terms acid solution and base solution , and give an example of why pH is important in biology.

Practice Assessment #1: Complete the following quiz on a piece of paper and place in your file folder!


3. Explain why ice floats.4. Compared to a basic solution of pH 8, the

same volume of an acidic solution at pH 5 has ____ times more hydrogen ion (H+).

Conclusion Guide (Page 3)5. Four elements make up 96% of the human body. . Which one of

the following is not one of those four major elements.A. CarbonB. NitrogenC. Iron D. OxygenE. Hydrogen.

6. When a covalent bond occurs,A. Protons are transferred from one atom to another.B. The atoms in the reaction become positively charged.C. An atom gives up one or more electrons to another atom.D. Ion are formed.E. Two atoms share electrons.


7. Which one of the following is represented in the figure to the right.

A. Surface tension.B. Ability of water to moderate temperature.C. Ability of ice to float.D. Evaporative cooling.E. Versatility of water as a solvent.

8. The pH of a solution:A. Inside most living cells close to 5.B. Can be quickly changed by the addition of a buffer.C. Can range from 0 to 14.D. Is acidic above the level of 7.E. Is determined by the relative amount of OH- ions.


9. A solution with a pH of 7 contains:A. More H + than OH- ions.B. More OH- than H+ ions.C. Only H+ ions.D. Only OH – ions.E. Equal amounts of H+ and OH- ions.

10. How does the polarity in the water molecule give water unique properties that make it essential to life?


11. Use the chart below to answers question A. and B. Print form and complete.

A. A small volume of dilute hydrochloric acid is place in a beaker and two drops a phenolphthalein are added. The solution remains colorless. A dilute solution of sodium hydroxide is then added drop by drop until a color change occurs. In what pH range does the color change occur? Describe the color change that occurs.

B. If you exhale carbon dioxide (CO2) into a solution of bromothymol blue, the solution terns from blue to yellow . Does CO2 dissolve in water to form an acid or a base?

Conclusion Guide (Page7)

Practice Assessment #2: Applying Scientific Methods to Unit 2.– A group of students carry out an experiment to determine

the action of the enzyme pepsin on protein digestion located within the human stomach. The students know that gastric juices found in the stomach contains water, pepsin, and hydrochloric acid. They use small equal sized pieces of cooked egg white as protein to be digested in their experiment.

Move forward to the next slide.


For this experiment, the students set up four test tubes and place an equal amount of the egg white into each test tube. Next, the students fill each test tube with a different liquid to a height of 3 centimeters. To test tube 1, the students add water; to test tube 2, they add hydrochloric acid (HCl diluted in water); to test tube 3 they add pepsin dissolved in water; and to test tube 4, they add pepsin solution and diluted hydrochloric acid. The students place the four test tubes in an incubator set at 37° C (body temperature.



After one day the students observe the results of the mixtures. The students then return the test tubes to the incubator and observe them again the next day. The table on the following slide is a record of the two day experiment.


Conclusion Guide (Page 10)Test Tube 1 day 2 days

1. Egg + water No change No change

2. Egg + Hydrochloric acid

No change No change

3. Egg + pepsin solution Liquid slightly cloudy, egg pieces unchanged

Liquid cloudy, egg pieces smaller

4. Egg + pepsin solution + hydrochloric acid

Liquid cloudy, egg pieces smaller

Liquid very cloudy, almost no egg remains

Answer the questions below.

1. Which test tube, during the experiment, is the control? Explain its purpose.

2. What is the independent variable in this experiment?

3. What is the dependent variable in this experiment?



4. What is the hypothesis on which this experiment is based?

5. Was the hypothesis correct? Explain?6. What kind of results would have shown that the

hypothesis for the experiment was not correct?7. What did the results from test tube 2 tell about protein

digestion in the human stomach?8. Write a conclusion to the experiment. Base your

conclusion on the experimental results.


* Place all completed work in your file folder.

Once you have completed the Practice Assessment please see your teacher for the unit 2 test.

Works Cited

http://www.cartoonstock.com/lowres/thl0022l.jpghttp://www.cartoonstock.com/directory/q/quadrille.asphttp://www.uhs.uusd.k12.ca.us/portfolio/2003/boxnate/3d/ice%20mountain%20pic.jpghttp://www.epa.state.oh.us/pic/kids/testtubes.jpghttp://www.newtownabbey.gov.uk/sustain/images/cartoon3.jpghttp://www.sproutnet.com/Test_Tubes_Lg.jpghttp://www.greece.k12.ny.us/ath/Web_files/Student_Clubs/MOLE/test_tubes.gifCopyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings.

After completing this test, move onto Unit # 3.

Documents

PowerPoint Learning Quest Biology 9 Unit 2: Basic Matter of Biology Created by Jeff Wolf and Mike Graff